Gas turbine energy supplementing systems and heating systems, and methods of making and using the same

ABSTRACT

Electrical power systems, including generating capacity of a gas turbine, where additional electrical power is generated utilizing a separately fueled system during periods of peak electrical power demand.

FIELD OF THE INVENTION

The invention relates generally to electrical power systems, includinggenerating capacity of a gas turbine, and more specifically to energystorage that is useful for providing additional electrical power duringperiods of peak electrical power demand and providing systems that keepthe gas turbine and steam turbine hot and ready to run thus reducingstart up time.

BACKGROUND OF THE INVENTION

Currently marginal energy is produced mainly by gas turbine, either insimple cycle or combined cycle configurations. As a result of loaddemand profile, the gas turbine base systems are cycled up duringperiods of high demand and cycled down or turned off during periods oflow demand. This cycling is typically driven by the Grid operator undera program called active grid control, or AGC. Unfortunately, becauseindustrial gas turbines, which represent the majority of installed base,were designed primarily for base load operation, when they are cycled, asevere penalty is associated with the maintenance cost of thatparticular unit. For example, a gas turbine that is running base loadcould go through a normal maintenance once every three years, or 24,000hours at a cost in the 2-3 million dollar range. That same cost could beincurred in one year for a plant that is forced to start up and shutdown every day.

Currently these gas turbine plants can turn down to approximately 50% oftheir rated capacity. They do this by closing the inlet guide vanes ofthe compressor, which reduces the air flow to the gas turbine, alsodriving down fuel flow as a constant fuel air ratio is desired in thecombustion process. Maintaining safe compressor operation and emissionstypically limit the level of turn down that can be practically achieved.The safe compressor lower operating limit is improved in current gasturbines by introducing warm air to the inlet of the gas turbine,typically from a mid stage bleed extraction from the compressor.Sometimes, this warm air is also introduced into the inlet to preventicing. In either case, when this is done, the work that is done to theair by the compressor is sacrificed in the process for the benefit ofbeing able to operate the compressor safely to a lower flow, thusincreasing the turn down capability. This has a further negative impacton the efficiency of the system as the work performed on the air that isbled off is lost. Additionally, the combustion system also presents alimit to the system.

The combustion system usually limits the amount that the system can beturned down because as less fuel is added, the flame temperaturereduces, increasing the amount of CO emissions that is produced. Therelationship between flame temperature and CO emissions is exponentialwith reducing temperature, consequently, as the gas turbine system getsnear the limit, the CO emissions spike up, so a healthy margin is keptfrom this limit. This characteristic limits all gas turbine systems toapproximately 50% turn down capability, or, for a 100 MW gas turbine,the minimum power that can be achieved is about 50%, or 50 MW. As thegas turbine mass flow is turned down, the compressor and turbineefficiency falls off as well, causing an increase in heat rate of themachine. Some operators are faced with this situation every day and as aresult, as the load demand falls, gas turbine plants hit their loweroperating limit and have to turn the machines off which cost them atremendous maintenance cost penalty.

Another characteristic of a typical gas turbine is that as the ambienttemperature increases, the power output goes down proportionately due tothe linear effect of the reduced density as the temperature of airincreases. Power output can be down by more than 10% from nameplateduring hot days, typically when peaking gas turbines are called on mostto deliver power.

Another characteristic of typical gas turbines is that air that iscompressed and heated in the compressor section of the gas turbine isducted to different portions of the gas turbine's turbine section whereit is used to cool various components. This air is typically calledturbine cooling and leakage air (hereinafter “TCLA”) a term that is wellknown in the art with respect to gas turbines. Although heated from thecompression process, TCLA air is still significantly cooler than theturbine temperatures, and thus is effective in cooling those componentsin the turbine downstream of the compressor. Typically 10% to 15% of theair that comes in the inlet of the compressor bypasses the combustor andis used for this process. Thus, TCLA is a significant penalty to theperformance of the gas turbine system.

Another characteristic of gas turbines is they typically take 20-30minutes to start up due to thermal loading considerations and the heatrecovery steam generator (HRSG) at combined cycle plant can take an houror more. This is a significant because the combined cycle plants arebeing used more frequently to balance renewable energy intermittencywhich fluctuates significantly in minutes.

SUMMARY OF THE INVENTION

The current invention provides several options, depending on specificplant needs, to improve the upper limit of the power output of the gasturbine, thus increasing the capacity and regulation capability of a newor existing gas turbine system.

One aspect of the present invention relates to methods and systems thatallow gas turbine systems to more efficiently provide the maximumadditional power during periods of peak demand because a separatelyfueled engine is used to drive the system, which eliminates significantparasitic loads typically associated with compressed air injectionsystems.

Another aspect of the present invention relates to an exhaustrecirculation system that eliminates the point source of emissions fromthe separately fueled engine.

Another aspect of the present invention relates to efficiencyimprovements utilizing the waste heat associated with the exhaust gasrecirculation system.

Another aspect of the present invention relates to a fueled inletchiller system where the waste heat from the separately fueled engineincreases the power output of the steam turbine thus maintaining orimproving efficiency of a combined cycle plant.

Another aspect of the present invention relates to an alternate use of apower boost system while the power plant is not running where compressedair is forced through the gas turbine and exhaust from the separatelyfueled engine is forced through the heat recovery steam generator(“HRSG”) to keep the entire gas turbine and steam turbine hot whichreduces start up time.

Another aspect of the present invention relates to an alternate use ofthe power boost system while the power plant is not running wherecompressed air is forced through the gas turbine and the HRSG to keepthe entire gas turbine and steam turbine hot which reduces start uptime.

Another aspect of the present invention relates to a power boost airinjection system that displaces cooling air normally taken from themid-stage or compressor discharge plenum of the gas turbine while at thesame time the exhaust from the separately fueled engine is used in theHRSG to produce additional power. The alternately supplied cooling airmay be similar in temperature and pressure to the air it is displacing,or cooler (which results in a reduction in cooling air requirements andimproved gas turbine (“GT”) efficiency).

Another aspect of the present invention relates to the use of relativelycool first stage nozzle cooling air leading to a reduction in coolingair requirements which translates to improved efficiency.

Another aspect of the present invention relates to a power boost systemdelivering relatively cool cooling air and during periods when thecombined cycle plant is not running, delivering hot compressed air tokeep the turbine section hot while at the same time using the separatelyfueled engine's exhaust in a packaged boiler to run steam through theHRSG and steam turbine to minimize the start up time of the completecombined cycle (“CC”) plant.

Another aspect of the present invention relates to utilizing aseparately fueled engine to drive hot compressed air into the combustiondischarge plenum while at the same time utilizing the excess lowerquality (i.e. lower temperature) heat available from the separatelyfueled engine's exhaust to preheat the GT's fuel, thus improvingefficiency of the GT.

One embodiment of the invention relates to a system comprising asupplemental compressor, at least one compressor, at least oneelectrical generator, at least one turbine (the at least one turbineconnected to the at least one generator and the at least onecompressor), and a combustion case (which is the discharge manifold forthe compressor).

Another advantage of another preferred embodiment is the ability toincrease the power output of the gas turbine system quickly withsupplemental compressed hot air being delivered by the separately fueledengine.

Another advantage of the preferred embodiment is the recirculation ofsome or all of the exhaust gas from the separately fueled engine thusminimizing or eliminating the emissions from a second source ofemissions at the power plant.

Another advantage of the preferred embodiment is the recirculation ofsome or all of the exhaust gas from the separately fueled engine thusminimizing or eliminating the cost associated with emissions clean up byusing the existing GT's emission control system.

An advantage of other preferred embodiments is the ability to increasethe power output while at the same time improving efficiency of theoverall system.

Another advantage of embodiments of the present invention is the abilityto improve the power output and efficiency of a conventional chillersystem.

Another advantage of embodiments of the present invention is the abilityto keep the gas turbine and steam turbine components warm while theplant is turned off thus reducing the start up time required.

Another advantage of some embodiments of the present invention is theability to improve the efficiency of the integrated power boost systemby reducing the heat that is otherwise wasted associated with cooledcooling air circuits of the GT.

Another advantage of some embodiments of the present invention is theability to deliver cooler cooling air to externally supplied turbinecomponents resulting in a reduction in the TCLA required for the GT andan improvement in the efficiency of the integrated power boost system.

Another advantage of some embodiments of the present invention is theability to deliver cooler cooling air to internally supplied turbinecomponents by preferential discharge or direct manifolding of thecooling air resulting in a reduction in the TCLA required for the GT andan improvement in the efficiency of the integrated power boost system.

Other advantages, features and characteristics of the present invention,as well as the methods of operation and the functions of the relatedelements of the structure and the combination of parts will become moreapparent upon consideration of the following detailed description andappended claims with reference to the accompanying drawings, all ofwhich form a part of this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic drawing of an embodiment of the present inventionhaving a supplemental energy system with a recuperated fueled engine,with exhaust gas recirculation, driving the supplemental compressorwhere some or all of the recuperated engine's exhaust is delivered tothe GT for further combustion.

FIG. 2 is a schematic drawing of an embodiment of the present inventionhaving a supplemental energy system with a recuperated fueled engine,with exhaust gas recirculation and fuel heating, driving thesupplemental compressor where some or all of the recuperated engine'sexhaust is delivered to the GT for further combustion and the lowquality waste heat is further used to heat the GT fuel.

FIG. 3 is a schematic drawing of an embodiment of the present inventionincorporating a supplemental power augmentation inlet chilling systemusing a separately fueled engine driven chiller, where the exhaust fromthe separately fueled engine is integrated into the GT's exhaust.

FIG. 4 is a schematic drawing of an embodiment of the present inventionwith a heat recovery steam generator heating system using the fueledengine exhaust, where both compressed air and the fueled engine'sexhaust is used to keep the simple or combined cycle plant warm whilethe plant is not running.

FIG. 5 is a schematic drawing of an embodiment of the present inventionincorporating a fast start system using compressed air, where a mixtureof compressed air and compressed exhaust from the fueled engine is usedto keep the simple or combined cycle plant warm while the plant is notrunning.

FIG. 6 is a schematic drawing of an embodiment of the present inventionwith turbine cool air supplement, where cool cooling air is supplied tothe high pressure cooling circuit of the gas turbine by the supplementalcompressor and the fueled engine and the fueled engine's exhaust isadded to the gas turbine's exhaust.

FIG. 7 is a schematic drawing of an embodiment of the present inventionwith downstream turbine nozzle cooled cool air supplement, where coolcooling air is supplied by the supplemental compressor and the fueledengine to the intermediate pressure cooling circuit and the fueledengine's exhaust is added to the GT's exhaust.

FIG. 8 is a schematic drawing of an embodiment of the present inventionwith first turbine nozzle cooled cooling air supplement, where coolcooling air is supplied by the supplemental compressor and the fueledengine to the first stage nozzle cooling circuit of the gas turbine andthe fueled engine's exhaust is added to the GT's exhaust.

FIG. 9 is a schematic drawing of an embodiment of the present inventionhaving fast start with air and steam injection, where cool cooling airis supplied by the supplemental compressor and the fueled engine to thefirst stage nozzle cooling circuit, the high pressure cooling circuit orthe intermediate pressure cooling circuit of the gas turbine, and thefueled engine's exhaust is used to produce steam for power augmentationwhen the gas turbine is operating and the compressed air and steam isused to keep plant warm when the gas turbine is not operating.

FIG. 10 is a schematic drawing of an embodiment of the present inventionwith fuel heating, having a supplemental energy system with arecuperated fueled engine driving the supplemental compressor, wheresome or all of the fueled engine's exhaust is used to heat the gasturbine's fuel.

FIG. 11 shows a gas turbine cycle of the type applicable to the presentinvention on a temperature-entropy of enthalpy-entropy diagram forSW501FD2 with 55 lbs/sec injection (+5.5%).

FIG. 12 shows a comparison of the work per pound mass required to pumpair from atmospheric conditions to elevated pressure for SW501FD2compressor compared to an intercooled compressor process.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the invention relates to methods and systems that allowgas turbine systems to run more efficiently under various conditions ormodes of operation. In systems such as the one discussed in U.S. Pat.No. 6,305,158 to Nakhamkin (the “'158 patent”), there are three basicmodes of operation defined, a normal mode, charging mode, and an airinjection mode, but it is limited by the need for an electricalgenerator that has the capacity to deliver power “exceeding the fullrated power” that the gas turbine system can deliver. The fact that thispatent has been issued for more than 10 years and yet there are no knownapplications of it at a time of rapidly rising energy costs is proofthat it does not address the market requirements.

First of all, it is very expensive to replace and upgrade the electricalgenerator so it can deliver power “exceeding the full rated power” thatthe gas turbine system can currently deliver.

Another drawback is that the system cannot be implemented on a combinedcycle plant without a significant negative impact on fuel consumption.Most of the implementations outlined use a recuperator to heat the airin simple cycle operation, which mitigates the fuel consumption increaseissue, however, it adds significant cost and complexity. The proposedinvention outlined below addresses both the cost and performanceshortfalls of the systems disclosed in the '158 patent.

One embodiment of the invention relates to a method of operating a gasturbine energy system comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing ambient air using a supplemental compressor driven by afueled engine, operation of which is which is independent of theelectric grid; and

(c) injecting the pressurized air into the combustor case.

According to one preferred embodiment, the warm exhaust from theseparately fueled engine is used to preheat fuel that is fed into thecombustor. Preferably, the fueled engine includes a jacket coolingsystem, and heat removed from the jacket cooling system is used topreheat fuel that is fed into the combustor.

According to another preferred embodiment, all or a portion of thefueled engine's exhaust is diverted to provide heat input to a heatrecovery steam generator when the gas turbine is not operating.

According to another preferred embodiment, the pressurized air producedby the fueled engine driven compression process is diverted to provideheat input to a heat recovery steam generator and/or the turbine whenthe gas turbine is not operating.

Another embodiment of the invention relates to a method of operating agas turbine energy system comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing ambient air and a portion of the exhaust gases from afueled engine, using a supplemental compressor driven by the fueledengine; and

(c) injecting the pressurized air and exhaust mixture into the combustorcase,

wherein operation of the fueled engine is independent of the electricgrid.

According to one preferred embodiment, warm exhaust from the separatelyfueled engine is used to preheat fuel that is fed into the combustor.Preferably, the fueled engine includes a jacket cooling system, and heatremoved from the jacket cooling system is used to preheat fuel that isfed into the combustor.

According to another preferred embodiment, all or a portion of thefueled engine's exhaust is diverted to provide heat input to a heatrecovery steam generator and/or the turbine when the gas turbine is notoperating.

According to another preferred embodiment, the pressurized air producedby the fueled engine driven compression process is diverted to provideheat input to a heat recovery steam generator and/or the turbine whenthe gas turbine is not operating.

Yet another embodiment of the invention relates to a method of operatinga gas turbine energy system comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing ambient air and all of the exhaust gases from a fueledengine, using a supplemental compressor driven by the fueled engine; and

(c) injecting the pressurized air and exhaust mixture into the combustorcase,

wherein operation of the fueled engine is independent of the electricgrid.

According to one preferred embodiment, warm exhaust from the separatelyfueled engine is used to preheat fuel that is fed into the combustor.Preferably, the fueled engine includes a jacket cooling system, and heatremoved from the jacket cooling system is used to preheat fuel that isfed into the combustor.

According to another preferred embodiment, all or a portion of thefueled engine's exhaust is diverted to provide heat input to a heatrecovery steam generator and/or the turbine when the gas turbine is notoperating.

According to another preferred embodiment, the pressurized air producedby the fueled engine driven compression process is diverted to provideheat input to a heat recovery steam generator and/or the turbine whenthe gas turbine is not operating.

Yet another embodiment of the invention relates to a method of operatinga gas turbine energy system comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing only the exhaust gasses from a fueled engine, using asupplemental compressor driven by the fueled engine; and

(c) injecting the pressurized air and exhaust mixture into the combustorcase,

wherein operation of the fueled engine is independent of the electricgrid.

According to one preferred embodiment, warm exhaust from the separatelyfueled engine is used to preheat fuel that is fed into the combustor.Preferably, the fueled engine includes a jacket cooling system, and heatremoved from the jacket cooling system is used to preheat fuel that isfed into the combustor.

According to another preferred embodiment, all or a portion of thefueled engine's exhaust is diverted to provide heat input to a heatrecovery steam generator and/or the turbine when the gas turbine is notoperating.

According to another preferred embodiment, the pressurized air producedby the fueled engine driven compression process is diverted to provideheat input to a heat recovery steam generator and/or the turbine whenthe gas turbine is not operating.

Yet another embodiment relates to a method of operating a gas turbineenergy system comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) cooling gas turbine inlet air using a supplemental refrigerationprocess driven by a fueled engine; and

(c) injecting exhaust from separately fueled engine into the exhaust ofthe gas turbine,

wherein operation of the fueled engine is independent of the electricgrid.

Yet another embodiment relates to a method of operating a gas turbineenergy system comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) cooling gas turbine inlet air using a supplemental refrigerationprocess driven by a fueled engine; and

(c) injecting exhaust from separately fueled engine into the exhaust ofthe gas turbine,

wherein operation of the fueled engine is independent of the electricgrid.

Yet another embodiment relates to a method of operating a gas turbineenergy system comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing ambient air using a supplemental compressor driven by afueled engine; and

(c) injecting the pressurized air into a rotor cooling air circuitupstream of a rotor air cooler,

wherein operation of the fueled engine is independent of the electricgrid.

Preferably, the exhaust from the alternately fueled engine is dischargedinto exhaust of the turbine.

Yet another embodiment relates to a gas turbine energy systemcomprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing ambient air using a supplemental compressor driven by afueled engine; and

(c) injecting the pressurized air into a rotor cooling air circuitdownstream of a rotor air cooler,

wherein operation of the fueled engine is independent of the electricgrid.

Preferably, the exhaust from the alternately fueled engine is dischargedinto exhaust of the turbine.

Another embodiment relates to a method of operating a gas turbine energysystem comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing ambient air using a supplemental compressor driven by afueled engine;

(c) injecting the pressurized air into the intermediate pressure coolingcircuit,

wherein operation of the fueled engine is independent of the electricgrid.

Preferably, the exhaust from the alternately fueled engine is dischargedinto exhaust of the turbine.

Another embodiment relates to a method of operating a gas turbine energysystem comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing ambient air using a supplemental compressor driven by afueled engine; and,

(c) injecting the pressurized air into the first stage nozzle coolingcircuit,

wherein operation of the fueled engine is independent of the electricgrid.

Preferably, the exhaust from the alternately fueled engine is dischargedinto exhaust of the turbine.

Another embodiment relates to a method of operating a gas turbine energysystem comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing ambient air using a supplemental compressor driven by afueled engine;

(c) injecting the pressurized air into a gas turbine cooling circuit;and

(d) injecting steam that is produced utilizing the heat from alternatelyfueled engine into the turbine,

wherein operation of the fueled engine is independent of the electricgrid.

Another embodiment relates to a method of operating a gas turbine energysystem comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other;

(b) pressurizing ambient air using a supplemental compressor driven by afueled engine;

(c) injecting the pressurized air into the turbine when the gas turbinesystem in not running,

wherein operation of the fueled engine is independent of the electricgrid

Another embodiment relates to a method of operating a gas turbine energysystem comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other; and

(b) injecting steam, that is produced utilizing the heat from analternately fueled engine, into a heat recovery steam generator whilethe gas turbine system is not running.

Another embodiment relates to a method of operating a gas turbine energysystem comprising:

(a) operating a gas turbine system comprising a compressor, a combustorcase, a combustor, and a turbine, fluidly connected to each other; and

(b) injecting the exhaust of a separately fueled engine into a heatrecovery steam generator while the gas turbine system is not running.

Yet another embodiment of the invention relates to an apparatusconfigured to perform the methods according to the invention including agas turbine system comprising a compressor, a combustor case, acombustor, and a turbine, fluidly connected to each other and one ormore additional components (e.g., a fueled engine) configured to performa method according to the invention.

The components of one embodiment of the present invention are shown inFIG. 1 as they are used with an existing gas turbine system (1). The gasturbine system (1) includes a compressor (10), combustor (12),combustion case (14), turbine (16) and generator (18). A fueled engine(151), which is either a reciprocating internal combustion engine, a gasturbine, or a similar machine that converts fuel into energy through anexothermic reaction such as combustion, is used to drive a multistageintercooled supplemental compressor (116) which compresses ambient air(115) and/or cooled exhaust (154) and discharges compressed air/exhaust(117). As those skilled in the art will readily appreciate, asair/exhaust in the supplemental compressor passes from one compressorstage to the next, the air is intercooled by use of a heat exchanger,such as a cooling tower, to reduce the work required to compress the airat the subsequent compressor stage. Doing so increases the efficiency ofthe supplemental compressor (116), which makes it more efficient thanthe compressor (10) of the gas turbine system (1).

This embodiment further includes a recuperator (144), which is a heatexchanger that receives the exhaust gas (152) from the fueled engine(151) and the compressed air/exhaust (117) from the supplementalcompressor (116). Within the recuperator (144), the hot exhaust gas(152) heats the compressed air/exhaust (117) and then exits therecuperator (144) as substantially cooler exhaust gas (153). At the sametime in the recuperator (144), the compressed air/exhaust (117) absorbsheat from the exhaust gas (152) and then exits the recuperator (144) assubstantially hotter compressed air/exhaust (118) than when it enteredthe recuperator (144). The substantially hotter compressed air/exhaust(118) is then discharged into the combustion case (14) of the gasturbine system (1) where it becomes an addition to the mass flow throughthe combustor (12) and turbine (16).

The warm exhaust gas (153) discharged from the recuperator (144) entersvalve (161) which directs some or all of the warm exhaust gas (153) tothe cooling tower (130) for further cooling. The cool exhaust gas (154)enters the inlet of the supplemental compressor (116). Additionalambient air (115) may also be added to the inlet of the supplementalcompressor (116). Any of the warm exhaust gas (153) that is not divertedto the cooling tower (130) by valve (161) can be discharged toatmosphere, to a fuel heating system, or to the GT exhaust (22).

The partial exhaust recirculation system of the present inventionreduces the emissions from the separately fueled engine while the 100%exhaust recirculation system eliminates the separately fueled engine assource of emissions. This can be very helpful for permitting reasons aswell as reducing cost as the existing gas turbine's exhaust clean upsystem can be used thus eliminating potential cost to the project.

It turns out that gasoline, diesel, natural gas, or biofuel and similarreciprocating engines are relatively insensitive to back pressure soputting the recuperator (144), on the fueled engine (151) does not causea significantly measurable effect on the performance of the fueledengine (151). FIG. 11 shows the gas turbine cycle on a TS or HS(temperature-entropy of Enthalpy-Entropy) diagram. Since temperature andenthalpy are proportional to each other (Cp), the vertical distancebetween the 14.7 psi ambient pressure (P10) and the compressor dischargepressure (“CDP”) process represents the compressor work required to pumpthe air up to CDP. The dotted line (P11) shows the compressor dischargepressure without injection, which is 218.1 psi, while the dashed line(P12) shows the compressor discharge pressure with injection, which is230.5 psi. The compressor discharge temperature increases from 770 F(P13) without compressed air injection, to 794 F (P14) with compressedair injection due to increased compression pressure ratio. Thisadditional 24 F results in 1% less fuel required to heat air to the 2454F firing temperature, and also results in +1.3% increase in compressorwork (as compared to the compressor work (P15) without compressed airinjection), or 3.5 MW. The temperature rise (and corresponding enthalpyrise) from approximately 750 F up to the turbine inlet temperature(“TIT”) of approximately 2454 F, the “firing temperature” (P16), whichrepresents the fuel input in British Thermal Units (“BTU”). The verticaldistance from CDP (P11, P12) to 14.7 psi (P10) on the right hand siderepresents the turbine work (P17), which is approximately two times thecompressor work (P15). The exhaust temperature drops with injection, dueto higher expander pressure ratio, from 987 F (P18) to 967 F (P19), adecrease of 20 F, or +0.81% more power per lb of air, or +4.7 MW at baseflow.

FIG. 12 shows a comparison of the work per pound mass required to pumpair from atmospheric conditions (14.7 psi) to a pressure slightly higherthan CDP (230 psi) so that it can be discharged in the CDP plenum. Asyou can see, the dashed curve represents a 3 stage intercooledcompressor with approximately 2.45 pressure ratio per stage (36 psiafter the first stage and 92 psi after the 2^(nd) stage, 230 psi afterthe 3^(rd) stage). The work to compress 1 lbm of air using anintercooled process (P20) is significantly less than a non-intercooledcompressor even considering similar stage compression efficiency.Realistically, because of intercooler pressure losses at each stage andthe fact air actually has to be pumped up to a higher pressure than CDPto effectively inject the air into the GT, more work is required thanFIG. 12 implies. However, on a per pound basis even considering theseconsiderations, the intercooled compressor uses less power than the work(P21) required by the GT to compress air for the turbine cycle.

FIG. 2 shows the embodiment of FIG. 1 where fuel heating is accomplishedby using the warm exhaust (153) to heat the fuel in a fuel heater (201).This further improves the efficiency of the power plant as fuel heatingreduces the BTU fuel input required to raise the compressor (10)discharge air up to the turbine inlet temperature which results in areduced quantity of fuel (24) that is required by the GT.

FIG. 3 utilizes an alternative technology, an inlet chilling system(401), for power augmentation. Inlet chilling works by providing a coldrefrigerant that is used to cool fluid that is circulated in a radiator(405). The cooled fluid (403) enters the radiator (405) and cools thegas turbine inlet air (20) passing through the radiator (405) such thatcool air (402) is discharged into the inlet of the GT causing the GTcycle to be more efficient and produce more power. The cooling fluid isthen discharged (404) from the radiator (405) warmer than when itentered and the chiller system (401) cools that fluid back down.Conventionally these systems are driven by electric motors, which placesa large parasitic load on the plant at the same time the plant is tryingto make additional power, which translates to a significant heat ratepenalty. When a separately fueled engine is used to drive the chiller,the parasitic load is eliminated. With the advent, current popularityand advancements, of efficient natural gas reciprocating engines, theexhaust from the reciprocating engine can be added to the gas turbineexhausts to make additional steam in the HRSG for the steam turbine.Some or all of this additional steam can also be extracted and used assteam injection for power augmentation if desired. Both of thesefeatures are significant efficiency improvements to a combined cycleplant. At simple cycle plants, an auxiliary boiler (not shown) canutilize the hot exhaust (352) to produce steam which can be used forsteam injection into the GT resulting in power augmentation.

FIG. 4 shows an alternate embodiment of FIG. 1 where a valve (501) isplaced in the exhaust (152) of the separately fueled engine (151) whichdiverts the exhaust (502) from the engine (151) to the HRSG (503) of acombined cycle plant where it is used to preheat or keep the system warmenabling quicker start times. When this system is operated, a hydraulicor mechanical clutch (504) is used to disengage the shaft of the fueledengine (151) from the compressor (116) such that it does not operate.

FIG. 5 is very similar to FIG. 4, however, the clutch for thesupplemental compressor (116) is eliminated and the compressor (116)provides compressed air/exhaust mixture (602) to the HRSG (503) and/orcompressed air/exhaust mixture (118) to the gas turbine via recuperator(114). This may be advantageous over low pressure exhaust as shown inFIG. 4 because the pressurized air/exhaust mixture can be more easilydirected to flow to areas than relatively low pressure air/exhaustmixture. Additionally, the separately fueled engine (151) will producehotter exhaust temperatures which may be desired for heating purposes.This configuration may be altered in such a way such that low pressure,but very high temperature exhaust (not shown) may be used to preheatareas of the HRSG (503) and GT that can utilize hotter temperature air,and the lower temperature compressed air/exhaust can be used in areas ofthe HRSG (503) and turbine that can utilize cooler temperature air.

FIG. 6 is a simplified approach to injecting compressed air into the gasturbine system (1) because the compressed air (117) is not required tobe heated because the air is used to replace cooled cooling air (602)that is normally supplied by the gas turbine (601) and cooled by air orsteam in the rotor air cooling system (155). Under normal operation of aSiemens Westinghouse 501F, 501D5, and 501B6 engine, for example,approximately 6.5% of the air compressed by the compressor (10) is bled(601) from the compressor discharge plenum (14) through a single largepipe, approximately 20″ in diameter. The bleed air (601) isapproximately 200-250 psi and 650-750 F. This hot air enters the rotorair cooling system (155) where air or steam is used to cool the bleedair (601). Heat is discharged to atmosphere (603) and wasted when air isused to cool the bleed air (601). However, if steam is used as thecoolant to cool the bleed air (601), heat is transferred from the bleedair (601) to the steam, thereby increasing the enthalpy of the steam,and the steam can then be used in the steam cycle. In both cases, thereis an efficiency improvement of the gas GT (1) cycle if no heat isdischarged at all. By injecting the cool pressurized air (117) upstream(601) or downstream (602) of the rotor air cooler (155), the heatrejected (603) is minimized or eliminated, thus improving the GT (1)cycle efficiency while at the same time effectively increasing the massflow of air through the combustor (12) section and turbine section (16).Most gas turbines have dedicated intermediate pressure compressor bleeds(701) that are used to cool the later stages of the turbine wherereduced pressures are required as shown in FIG. 7. Also, all gasturbines feed the first vane cooling circuit with the highest pressureavailable, which is in the compressor discharge wrapper (14) (orcombustor case) as shown in FIG. 8. Depending on the injection location,the rotor cooling air as shown in FIG. 6, the intermediate pressurecooling as shown in FIG. 7 or the first vane cooling as shown in FIG. 8,different pressures are required. These pressures can be supplied by theexit of the intercooled supplemental compressor (116) or from earlierstages of the intercooled supplemental compressor (116) for lowerpressure applications. In all cases, since this type of injectionutilizes little (not shown) or no recuperation to heat the air up, theexhaust (152) of the separately fueled engine can be added to the gasturbine exhaust (22) as shown to increase the exhaust energy for acombined cycle plant. If the power boost system of the present inventionis located at a simple cycle plant, the hot exhaust (152) can beutilized in a packaged boiler (901) to make steam for injection into thegas turbine (903) as shown in FIG. 9. Since the TurboPHASE packages (asthe present invention is called) are meant to be modular, it may beadvantageous to incorporate the packaged boiler (901) on at least one ofthe units such that during off peak times the TurboPHASE modular packagecan be run to keep the gas turbine warm with pressurized hot air (117)circulation and keep the steam turbine/HRSG (503) warm with steamcirculation to reduce the starting time requirement.

There are further improvements in efficiency that can be achieved byincorporating the low quality heat. For example in FIG. 10, the gasturbine fuel input (24) can be preheated (1023) with heat from thefueled engine's jacket cooling system (1011 and 1012). By doing this,the plant cooling requirements will be reduced and the gas turbine fuelwill be preheated (1023) prior to entering the fuel heater (201), thusrequiring less heat input to achieve a desired fuel temperature, or tobe able to achieve a higher fuel temperature. FIG. 10 also shows analternate embodiment where the exhaust (153) from the recuperator (144)is used to add the final heat into the gas turbine fuel (1024) prior toinjection into the GT. In this case, the exhaust gas (153) of thealternately fueled engine (151), after flowing through the fuel heater(201) and being discharged (1002) is relatively cool.

While the particular systems, components, methods, and devices describedherein and described in detail are fully capable of attaining theabove-described objects and advantages of the invention, it is to beunderstood that these are the presently preferred embodiments of theinvention and are thus representative of the subject matter which isbroadly contemplated by the present invention, that the scope of thepresent invention fully encompasses other embodiments which may becomeobvious to those skilled in the art, and that the scope of the presentinvention is accordingly to be limited by nothing other than theappended claims, in which reference to an element in the singular means“one or more” and not “one and only one”, unless otherwise so recited inthe claim.

It will be appreciated that modifications and variations of theinvention are covered by the above teachings and within the purview ofthe appended claims without departing from the spirit and intended scopeof the invention.

The invention claimed is:
 1. A method of operating a gas turbine energysystem comprising: (a) operating a gas turbine system comprising acompressor, a combustor case, a combustor, and a turbine, fluidlyconnected to each other; (b) pressurizing ambient air using asupplemental compressor driven by a fueled engine; (c) injecting saidpressurized air into a rotor cooling air circuit upstream of a rotor aircooler; and (d) adding exhaust of the fueled engine to exhaust of theturbine, the fueled engine exhaust bypassing the combustor.
 2. Themethod of claim 1, wherein said pressurized air is not heated by saidfueled engine.
 3. The method of claim 1, wherein injecting saidpressurized air from said supplemental compressor into said rotorcooling air circuit increases mass flow through said combustor.
 4. Themethod of claim 1, wherein injecting said pressurized air upstream ofsaid rotor cooling air circuit, minimizes heat rejected from said rotorcooling air circuit.
 5. The method of claim 1, wherein said pressurizedair has a lower temperature than a compressed air in said rotor coolingair circuit.
 6. A method of operating a gas turbine energy systemcomprising: (a) operating a gas turbine system comprising a compressor,a combustor case, a combustor, and a turbine, fluidly connected to eachother; (b) pressurizing ambient air using a supplemental compressordriven by a fueled engine; (c) injecting said pressurized air into arotor cooling air circuit; and (d) adding exhaust of the fueled engineto exhaust of the turbine, the fueled engine exhaust bypassing thecombustor.
 7. The method of claim 6, wherein the pressurized air isinjected upstream of a rotor air cooler.
 8. The method of claim 7,wherein injecting said pressurized air minimizes heat rejected from saidrotor cooling air circuit.
 9. The method of claim 6, wherein saidpressurized air is not heated by said fueled engine.
 10. The method ofclaim 6, wherein injecting said pressurized air from said supplementalcompressor into said rotor cooling air circuit increases mass flowthrough said combustor.
 11. The method of claim 6, wherein saidpressurized air has a lower temperature than a compressed air in saidrotor cooling air circuit.